In many industrial applications, air or gas flow through a conduit can become turbulent when objects or bends exist in the flow path. These objects or bends may be necessitated by physical dimensions of the application equipment or layout design constraints. The deflections caused by objects or bends in the flow path produce a non-uniform or asymmetrical flow velocity across the cross-section of the flow path. Bends or angles in the flow conduit as well as rotating propulsion equipment in the flow stream may cause additional turbulence in the form of vortices or swirls transverse to the flow path. Non-uniform distribution of gas, in conjunction with turbulence, is problematic in devices such as burners or apparatus requiring flow metering.
To attenuate or eliminate such turbulence, long and narrow straight flow channels are conventionally used to straighten the flow or create a more uniform flow distribution. To be effective, however, these channels require a large length-to-diameter (L/D) ratio. In some applications, a 30:1 L/D ratio or higher may be required. The use of such an elongated flow path may be impractical in many industrial applications where dimensional or physical constraints in the installation facilities make it impossible to incorporate long and straight channels. As a result, various diffuser or straightener structures have been used in the prior art to attenuate swirl or turbulence in an effort to provide a more uniform flow distribution. Honeycomb structures, for example, have been used as means to direct and straighten flow through a duct or channel. Honeycomb or like structures are inadequate in many applications, however, because they cannot attenuate asymmetrical flow turbulence unless each honeycomb segment has a large length-to-diameter ratio in itself. Additionally, many flow straightening structures create a significant resistance in the flow path thereby creating an excessive and undesirable pressure drop.
In addition to the above, many flow-straightening devices suffer from complexity of construction, making fabrication difficult and the resulting procurement cost undesirable.